The objective of the research is to establish the function of ergothioneine, a thiolimidazole betaine which is widely distributed in mammalian, plant, and microbial cells, in order to gain knowledge of the significance of varying levels of ergothioneine in human tissues to normal and pathological metabolic processes. Investigations will emphasize microbial studies, and will include the possible relationships of ergothioneine and related compounds to aerobic processes, to alternate pathways of metabolism, and to protection against ultraviolet radiation. Studies will include work with whole organisms and with isolated enzymes.